Flooding has cut roads and forced the closure of the train line between Townsville and Cairns after torrential rain across north Queensland.

Hundreds of millimetres of rain has fallen as a result of ex-tropical cyclone Oswald and central Queensland communities are now preparing for flooding as the system moves south.

The ex-cyclone is now about 85 kilometres west of Cape Tribulation and is moving slowly south, bringing damaging winds and heavy rain.

Senior Forecaster Ken Nato warns the big rain is heading south of Townsville.

"Today and tomorrow we are expecting towns like Bowen and Townsville which is already starting to see some of the weather, down to Mackay and even down to St Lawrence by tomorrow," he said.

Queensland Rail (QR) has been forced to close the Townsville to Cairns rail line because of water over the tracks at a number of places, including Tully, Bilyana, Aloomba, and Deeral.

Crews will assess damage when flooding subsides.

A QR spokeswoman says passengers will have to wait in the cities because they cannot arrange alternative transport due to road closures.

About 130 millimetres of rain has been dumped on Ingham, north of Townsville, in the past three hours.

Residents there are being urged to stock up on supplies as the Herbert River continues to rise and is expected to peak at 11 metres later today.

Tully has recorded more than 600 millimetres of rain in 48 hours, and almost 200mm has been recorded at Mission Beach and near Cairns.

Further north, Weipa has recorded 300 millimetres of rain since 9:00am (AEST) yesterday.

Senior forecaster David Grant says more heavy falls are likely and warnings are in place.

"There'll be intense rainfall around in the vicinity of the ex-tropical cyclone, however, in the general area right across north Queensland in association with the monsoon trough we will see some heavy rainfall right across the region," he said.

"As a result we do have a severe weather warning for heavy rainfall and flash flooding."